Apparatus for paying out wire



Nov. 7, 1967 E. u. LANG APPARATUS FOR PAYING OUT WIRE 2 Sheets-Sheet 1Filed Feb. 23, 1965 $7 WJW W Nov. 7, 1967 E. u. LANG 3,351,302

APPARATUS FOR PAYING OUT WIRE Filed Feb. 25, 1965 2 Shets-Sheet zWig-{i219 United States Patent 3,351,302 APPARATUS FOR PAYiNG GUT WIREErnest U. Lang, Niles, Mich, assignor to National- Standard Company,Niles, Mich, a corporation of Delaware Filed Feb. 23, 1965, Ser. No.434,259 tClaims. (Cl. 242-4562) ABSTRACT 0F THE DISCLOSURE The presentinvention relates to apparatus for paying out coiled material, such aswire, wound on a reel from the reel to a place of use of the material.

In many utilizations of wire such as welding wire and wire for springand staple fabricating machines, relatively low wire speed delivery isdesirable, such as of the order of 150 feet per minutes or less. In suchinstances it has been the practice to use so called small packages ofwire as the supply source in that presently known let-off stands are notsatisfactorily operable to provide for the feeding of wire undersubstantially constant tension at speeds of the order noted. It is onepurpose of the present invention to provide let-off apparatus forsupporting a large reel package of wire, for example, of the order of1000 pounds, from which wire may be Withdrawn at low pulling forces, forexample, of the extent of 6 pounds, and at low linear speeds of theaforenoted order and under substantially constant tcnsion.

Further, presently known let-ofi apparatus embody a pivotally mountedfestoon arm for supporting a sheave over which wire from a reel istrained in drawing the Wire off of the reel, and which festoon arm byits own weight or by being spring loaded solely provides for actuating abrake for braking the reel when withdrawal of wire from the reel isterminated. In such known constructions, a large releasing force of thewithdrawn wire is required to actuate the reel brake and hence are notsatisfactory in the typical instances above mentioned. It is a furtherpurpose of the present invention to provide a let-off apparatusembodying brake means for yieldingly braking the reel at low braketorque as wire is withdrawn therefrom, and which is self-energizing uponreduction of the small or slight releasing force of the withdrawn wireto provide positive or non-yielding application of the brake means tothe reel under relatively high brake torque.

In view of the foregoing it is an object of the present invention toprovide a let-01f apparatus embodying festoon means for storing materialdrawn off a coil carried by a reel supported on the stand for theapparatus, and means for the festoon means operable to maintain materialdrawn from the festoon means under substantially constant tension.

A further object of the invention is to provide a letolf apparatus inwhich the reel carries a brake drum and brake shoe means therefore isassociated with the festoon means, and together with means for normallyyieldingly engaging the brake shoe means at low torque with the brakedrum when material is being drawn olf the reel, and, in which, such lastnamed means effects self en- Patented Nov. 7, 1967 ergization of thebrake shoe means into substantially nonyielding engagement at high braketorque with the brake drum upon termination of withdrawal of materialfrom the festoon means.

The above and other objects and advantages of the invention will beapparent from the following detailed de scription of a preferredembodiment of the invention.

Now in order to acquaint those skilled in the art with the manner ofconstructing and operating a let-off ap paratus in accordance with theprinciples of the present invention, there is described below inconnection with the accompanying drawings a preferred embodiment of theinvention.

In the drawings:

FIGURE 1 is a side elevational view of a let-off apparatus constructedin accordance with the principles of the present invention;

FIGURE 2 is an end elevational view looking toward the rear of thelet-off apparatus of FIGURE 1;

FIGURE 3 is a detail side elvational view of brake shoe means forengaging a brake drum on a reel carrying a coil of wire mounted on thestand of FIGURES 1 and 2, and showing a slide member of brake shoemounting means for mounting the brake shoe means on the festoon arm offestoon means of the stand; and

FIGURE 4 is a detail view of shaft means for supporting a reel for acoil of wire, and a brake drum for the reel embodied in the apparatus ofFIGURES 1 and 2.

Referring now to FIGURES l and 2 of the drawings, there is shown alet-off apparatus constructed in accordance with the present inventionand which in the main comprises frame means 1, a reel and shaft assembly2 supported on the frame means 1, brake means for the shaft and reelassembly indicated generally at 3, and festoon means for wire withdrawnfrom a coil on the reel indicated by the reference numeral The framemeans 1 comprises a pair of laterally spaced apart side frame members 5and 6 extending upwardly from a base member 7. The side frame members 5and 6 intermediate their ends have support means 8 and 9 mounted on theouter surfaces thereof and which support means 3 and 9 have upper camfollower supporting surfaces 10 lying above the upper edges of the sideframe members 5 and 6 for purposes to be herinafter described in greaterdetail, it being sufiicient for the present to note that the reel andshaft assembly 2 is mounted thereon for rotation about a fixedhorizontal axis to provide for withdrawing of wire from the reel. Itwill be understood that the letofif apparatus of the present inventionhas utility for use With coils of material other than wire such asnatural or synthetic filaments and for strands comprising monofilamentor multifilament coiled material. The word wire" is thus used herein inthe generic sense to mean metal Wire or other coiled filaments astypified by those last above noted.

The festoon means 4- comprises a first fixed standard 14 securelymounted outwardly of and on side frame member 5 to project upwardly andforwardly of the main frame 1 and which at its outer end carried a firstwire guide, such as a sheave 16, rotatably mounted about a fixed axis atthe outer end of axle pin 17 mounted at the upper end of the standard toposition the sheave is in a vertical plane lying substantially centrallybetween the side frame members 5 and 6. The festoon means 4 furthercomprises a festoon arm 18 pivotally mounted at its lower end in abearing block 19 on the base 7 of the main frame 1 and lying inwardly ofthe inner surface of the side frame member 5. The festoon arm 18 isdefined by a first leg portion 22 extending generally forwardly andupwardly of the main frame 1, a second leg portion 23 extendinggenerally upwardly and rearwardly of the 3 frame, and a third legportion 24 extending further rearwardly and upwardly of the main frame,and which at its outer end carries a second wire guide in the form of asheave 25 rotatably mounted about a fixed axis on an axle pin 26 carriedat the outer end of the festoon arm. Festoon arm 18 is normally biasedfor rotation in a clockwise direction as viewed in FIGURE 1 tending tospace apart the first and second wire guide sheaves 16 and 25 forstorage of wire withdrawn from the coil. The wire w from the coil isadapted to be trained over the first sheave 16 and then to and aroundthe second sheave 25 from which it extends to its place of utilization.In accordance with the present invention, spring means, indicatedgenerally at 30, is arranged between the festoon arm 18 and the mainframe 1 of the stand to provide, as will be hereinafter described, forthe drawing of wire otf of the coil under substantially constant tensionover a predetermined range of pivotal movement of the festoon arm 18 andwithin the wire storage capacity of the festoon means. The spring means30, as seen in FIGURE 1, comprises a link 32 pivotally secured at itsouter end to leg portion 23 of the festoon arm 18 close to the junctureof the latter with the first leg portion 22, and a coil tension spring33, connected at its inner end to the other or outer end of the link 32,and with the outer or other end of coil spring 33 being anchored, as at34, on an anchor member 35 rigidly connected to the base 7 of theframe 1. It will be observed that the axis of the spring means 33 asindicated, at xx, extends angularly upwardly and forwardly from the baseof the stand and in converging relation to leg portion 22 of the festoonarm 18. As shown in FIGURE 1, a resilient spring bumper 37 is mountedinwardly of the inner surface of the side frame member and in positionto be engaged by the leg portion 22 of the festoon arm 18 to limitpivotal movement of the festoon arm 18 around its pivot 19 in acounterclockwise direction. Also, as shown in FIGURE 1, a reactionmember 36 attached to side frame member 5 limits the clockwise pivotalmovement of the festoon arm caused by self energization of brake means3,'hereinafter described in greater detail, upon termination ofwithdrawal of the wire.

In the apparatus thus far described it will be noted that upon drawingwire w over sheave 16 and sheave in the initial movement of the wire atthe source of use the festoon arm 18 will move in a counterclockwisedirection about its pivot 19 initially taking out the wire storedbetween the sheaves 16 and 25. In such initial starting operation theinertia of the reel and the coil of wire thereon is overcome. Thefestoon arm may rock to engage the resilient bumper 37 should wirespeeds in excess of about 150 feet per minute be attained. Of course, alarger wire tension will be needed to accelerate a 1000 lb. reel abovethe constant tension design speed of the apparatus. Thereafter, thefestoon arm 18 will back off or move in a counterclockwise direction andthe festoon arm will shortly assume a position in which there is nohunting, that is with the hereinbelow described brake shoe means 48lightly engaging a brake drum 44 carried by the reel. It will be notedthat in relative movement of sheave 25 toward and away from sheave 16 ofthe festoon means that the effective lever arms of the spring means willvary to provide for constant tension of the withdrawn wire over apredetermined range of movement of festoon arm such as the distance Yindicated on FIGURE 1. In this regard, it will be observed upon movementof the festoon arm 18 in a counterclockwise direction from the positionshown the axis x--x shifts downwardly and forwardly shortening thedistance indicated at L between the pivot 19 of the festoon arm 18 andthe axis xx of the spring means 30 thus decreasing the effective leverarm in proportion to increasing the force component of spring 33 as itis linearly extended. The distance L between the center line x-x of thespring means 30 and the pivot 19 of the festoon arm 18 upon movement offestoon arm 18 will vary providing a varying effective lever arm for theuniform maintenance of torque and withdrawal of wire w undersubstantially constant tension in the predetermined range spaced apartnormal storage capacity between the sheaves 16 and 25. When the sheave25 exceeds its normal storage capacity position the spring bumper means37 effects gradually increasing tension to the withdrawn wire asindicated at z. In connection with loading a reel having a coil of wirethereon onto the stand as will be later described it will be observedthat a hook member 40 is pivotally mounted on the pin 17 supportingsheave 16 and which is adapted to be engaged with a pin 42 on the legportion 24 of the festoon arm 18 to hold the festoon arm 18 wellforwardly of the frame.

In connection with the aforementioned components providing forsubstantially constant tension of wire withdrawn from a reel over apredetermined range of move ment of the festoon arm, it will be observedthat brake means, indicated generally at 3, provides for the retardingrotation of the reel so that it does not overrun wire being withdrawnfrom the coil. The brake means 3 as best seen in FIGURES 1, 3 and 4comprises a brake drum 44 suitably mounted on shaft means 45 of the reeland shaft assembly 2, and from which a pair of pins 46 project axiallyand into openings provided in the adjacent reel side plate 47. The brakemeans 3, as seen in FIGURES 1 and 3, further comprises brake shoe means48 defined by a pair of leg members 52 and 53 which at their divergingouter end portions carry brake shoes 54 and 55 for braking engagementwith the P ripheral surface of the brake drum 45. A transversereinforcing plate 56 connects the leg members 53 and 54 inwardly oftheir diverging end portions, and a spring holder, in the form of arigid hollow pipe 57, is mounted on the plate 56 to lie between parallelspaced apart upper portions 58 and 59 of the arms 52 and 53. A platemember 60 extends across and is secured to the upper ends of the legs 58and 59. Brake spring means in the form of coil spring 62 is received andsupported in the rigid hollow pipe 57. Brake shoe mounting means formounting the brake shoe means 48 on the festoon arm 18 comprises a slidemember 65 mounted between the parallel portions 58 and 59 of the legs 52and 53 of the brake shoe means for movement between. end plate 60 andthe open upper end of hollow pipe 57. The slide member 65 is formed withan opening into which a pin 66 carried by the leg portion 23 of thefestoon arm 18 is received. The slide 65 is thus mounted for slidingrelation between the arms 58 and 59 of the brake shoe means in responseto movement of the festoon arm 18. A coil spring 67 extends betweenfestoon arm 18 and brake shoe means 48 to position the latter withrespect to the brake drum 44.

In normal operation of drawing wire w from the reel, the brake springmeans 62 will be loaded between the slide 65 and the plate 56 of thebrake shoe means to yieldingly bias or engage the brake shoes 54 and 55into engagement with the periphery of the drum over a predeterminedrange of movement of the festoon arm toprevent the reel from overrunningthe wire being withdrawn from the reel. Upon movement of the festoon 18to a predetermined end position in the clockwise direction at which theslide 65 fully collapses the brake spring means 62 within the hollowpipe 57, the slide 65 will then rigidly engage the hollow pipe 57 and,when this occurs, the brake shoe means 48 will self energize intosubstantially non-yielding engagement with the surface of the brake drum44. The foregoing self-energization of the brake shoe means 48 with thebrake drum 44 results due to the relationship of the axis of rotation ofbrake drum 44 about the fixed horizontal axis of shaft means 45 and thearcuate path of movement of pivot 66 for the brake shoe means 48 carriedby festoon arm 18 as defined by its pivot 19. Thus, as seen in FIGURE 1,as the festoon arm rotates in a clockwise direction about its pivot 19,the pivot 66 follows an arcuate path advancing toward the axis of shaftmeans 45 so that at a predetermined position of festoon arm 18 the brakeshoe means 48 engage the brake drum to thus effect se-lf-energization ofthe brake shoe means into substantially non-yielding engagement with thebrake drum. The brake torque thus applied to the brake drum is manytimes that of the yielding frictional braking action in the normaloperation of drawing wire w from the reel. Thus, upon discontinuingdrawing of wire from the reel or breakage of the wire when the festoonarm 18 approaches its predetermined end clockwise position, large orhigh brake torque through self-energization of the brake shoe meansarrests movement of the reel and holds it against rotation. Thus, in theoperation of the apparatus, a small or slight releasing force issufiicient for the wire to be withdrawn from the spool. But, as thefestoon arm is positioned toward its predetermined end clockwiseposition the self-energizing action of the brake means provides forapplication by toggle action of the brake shoe means to the brake drum.

The apparatus shown in the drawings provides for the facile and easymanual loading of a heavy reel and wire coil thereon onto the frame 1.It will be observed that the frame means is provided with a tread member70 having a surface 71 inclined upwardly and toward the front end of theframe 1. A pair of ramps 73 and 74 are securely mounted to the sideframe plates 5 and 6 at the inner surfaces thereof and at the upperedges of the side frame members to dispose the ramps 73 and 74 withtheir upper surfaces 75 lying above the upper edges of the side plates 5and 6. The edge ramp surfaces 75 are inclined slightly upwardly andinwardly of the frame toward the front end thereof and theaforementioned supporting means 8 and 9 are disposed in juxtaposition ofthe ramps 73 and 74. The cam follower supporting surfaces 10 of thesupporting means 8 and 9 lie laterally outwardly of the surfaces of theramps 73 and 74 to receive cam followers 83) and 81 mounted,respectively, at opposite ends of the shaft means 45 of the assembly 2.The cam followers 80 and 81 are preferably low friction rollers and aresecured to the ends of the shaft 46 in any suitable manner. Brackets '82and 83 as best seen in FIGURES 1 and 2 have latches 84 and 85 pivotallymounted thereon so that when the cam followers 80 and 81 are supportedon the cam follower surfaces 10 of the supporting means 8 and 9 thelatches 84 and 85 may be swung in position over the cam followers toretain the reel and drum assembly in position on the frame as shown inFIGURE 1.

In loading a reel with a coil of wire thereon onto the frame the festoonarm 18 is first disposed to its end counterclockwise position to disposethe brake shoe assembly 3 in position free of the brake drum of the reelto be placed on the frame. The festoon arm is held in such position asabove described by the aforementioned latch and pin 42. The reel is thenpositioned with the portions of the peripheries of the reel sides inengagement with the inclined surface 71 of the tread 70, and uponmovement of the reel on the peripheries of its rims inwardly of theframe, the reel is raised slightly to dispose portions of the shaftmeans onto the surfaces 75 of the ramps 73 and 74 with the reel thenrolling into the frame on these ramp surfaces to the point where the camfollowers $0 and 81 engage with the cam follower supporting surfaces 1%of the support means 8 and 9, respectively. Thereafter, the latches 84and 85 are disposed to the position shown in FIGURE 1 to retain the reelin position on the frame. The latch 40 may then be released from the pin42 and the festoon arm moved in a counterclockwise direction to engagethe brake shoes of the brake shoe means with the surface of the brakedrum. Thereupon, upon stringing of the wire through the festoon asbefore described, the let-off apparatus is ready for operation. It willbe observed that in loading a reel onto the let-01f stand as abovedescribed that only a portion of the necessary work is achieved byrolling the peripheries of the reel sides up inclined surface 71 of thetread 70. A preliminary roll of less than one inch is sufficient toeasily roll the reel to the point at which shaft means 45 is depositedonto surfaces 75 of the ramps 73 and 74. Thereafter, and during themajor portion of the work, a large mechanical advantage is availablesince the reel must rotate more than one revolution on the periphery ofits shaft means 45 while only a small force is applied manually on theperiphery of the reel sides until disposal of the cam followers and 81on the cam follower surfaces 10 of the support means 8 and 9.

While a preferred embodiment of the invention has been shown anddescribed, it will be understood'that various modifications andrearrangements may be made therein without departing from the spirit andscope of the invention.

The invention claimed is:

1. In an apparatus of the class described the combination of framemeans, a reel having a coil of wire or the like wound thereon, means forrotatably supporting said reel on said frame means, festoon meanscomprising a first wire guide mounted on said frame means, a festoon armpivotally mounted at one end thereof on said frame means, and a secondwire guide mounted at the other end of said festoon arm and movablerelative to said first wire guide by pivotal movement of said festoonarm about its pivot for storing wire drawn from said reel between saidfirst and second wire guides, means extending between said festoon armand said frame means for maintaining wire drawn ofl of said second wireguide under substantially constant tension over a predetermined range ofpivotal movement of said festoon arm, a brake drum carried by said reel,brake shoe means for said brake drum, brake mounting means for mountingsaid brake shoe means on said festoon arm, brake spring means betweensaid brake mounting means and said brake shoe means for yieldinglybiasing said brake shoe means into engagement with said brake drum overa predetermined range of movement of said festoon arm, and said brakemounting means at a predetermined position of said festoon armcollapsing said brake spring means to dispose said brake shoe means inself-energizing and substantially non-yielding engagement with saidbrake drum.

2. In an apparatus of the class described the combination of framemeans, a reel, means for rotatably supporting said reel on said framemeans, festoon means comprising a festoon arm mounted for movement onsaid frame means, a brake drum carried by said reel, brake shoe meansfor said brake drum, brake mounting means for mounting said brake shoemeans on said festoon arm, and brake spring means between said brakemounting means and said brake shoe means for yieldingly biasing saidbrake shoe means into engagement with said brake drum over apredetermined range of movement of said festoon arm, and said brakemounting means at a predetermined position of said festoon armcollapsing said brake spring means to dispose said brake shoe means inself-energizing and substantially non-yielding engagement with saidbrake drum.

3. In an apparatus of the class described the combination of framemeans, a reel having a coil of wire or the like wound thereon, means forrotatably supporting said reel on said frame means, festoon meanscomprising'a first wire guide mounted on said frame means, a festoon armmounted for pivotal movement on said frame means, and a second wiregniide carried by said festoon arm and movable relative to said firstwire guide over a predetermined range of movement of said festoon armfor storing wire drawn from said reel between predetermined spaced apartpositions of said first and second wire guides, a brake drum carried bysaid reel, brake shoe means for said brake drum, brake mounting meansfor mounting said brake shoe means on said festoon arm, brake springmeans between said brake mounting means and said brake shoe means foryieldably biasing the latter into engagement with said brake drum oversaid predetermined range of movement of said festoon arm, and said brakemounting means at a predetermined position of said festoon arm spacingsaid first and second wire guides a predetermined maximum distance apartcollapsing said brake spring means to dispose said brake shoe means inselfaenergizing and into substantially non-yielding engagement with saidbrake drum.

4. In an apparatus of the class described the combination of framemeans, a reel having a coil of wire or the like wound thereon, means forrotatably supporting said reel on said frame means for drawing wire fromsaid coil, festoon means for wire withdrawn from said reel comprising afirst wire guide mounted on said frame means, a festoon arm mounted forpivotal movement on said frame means, and a second wire guide carried bysaid festoon arm and movable relative to said first wire guide over apredetermined range of movement of said festoon arm for storing wiredrawn from said reel between predetermined spaced apart positions ofsaid first and second wire guides, a brake drum carried by said reel,brake shoe means for said brake drum, brake mounting means for mountingsaid brake shoe means on said festoon arm comprising a slide memberpivotally mounted on a fixed axis on said festoon arm and slidablymounted in said brake shoe means, brake spring means between said slidemember and said brake shoe means for yieldingly biasing the latter intoengagement with said brake drum over a predetermined range of movementof said festoon arm, and said brake mounting means at a predeterminedposition of said festoon arm spacing said first and second wire guides apredetermined maximum distance apart collapsing said brake spring meansto dispose said brake shoe means in self-energizing and substantiallynon-yielding engagement with said brake drum.

5. In an apparatus of the class described the combination of framemeans, a reel having a coil of wire or the like wound thereon, means forrotatably supporting said reel on said frame means for drawing wire fromsaid reel, festoon means comprising a first wire guide mounted on saidframe means, a festoon arm mounted for pivotal movement on said framemeans, and a second wire guide carried by said festoon arm and movablerelative to said first Wire guide over a predetermined range of movementof said festoon arm for storing wire drawn from said reel betweenpredetermined spaced apart positions of said first and second wireguides, a brake drum carried by said reel, brake shoe means for saidbrake drum, a rigid spring holder open at one end and fixed to saidbrake shoe means, brake mounting means for mounting said brake shoemeans on said festoon arm comprising a slide member pivotally mounted ona fixed axis on said festoon arm and slidably mounted in said brake shoemeans, brake spring means in said spring holder extending through theopen end of the latter for engagement with said slide member foryieldingly biasing said brake shoe means into engagement with said brakedrum and a predetermined range of movement of said festoon arm, and saidslide member at a predetermined position of said festoon arm spacingsaid first and second Wire guides a predetermined maximum distance apartcollapsing said brake spring means within said spring holder and rigidlyengaging said one end thereof to dispose said brake shoe means intoself-energizing and substantially non-yielding engagement with saidbrake drum.

References Cited UNITED STATES PATENTS 2,215,651 9/1940 Pierce 5242156.2 X 2,285,654 6/1942 Hanna et al 242 2,419,808 4/1947 Wirth242-156.2 2,562,990 8/1951 Peebles 242156 X 2,879,011 3/ 1959 Nelson242156.2 2,905,406 9/ 1959 Falck-Pedersen 24275.43 2,920,840 1/1960Cooper 242156.2 2,983,468 5/1961 Perrella 242-156.2 3,081,957 3/1963 VanDe Bilt 242-156.2 X 3,222,008 12/ 1965 Purzycki 24275.43 3,223,35212/1965 Fuller et a1. 242-1562 FOREIGN PATENTS 780,164 7/ 1956 GreatBritain.

STANLEY N. GILREATH, Primary Examiner.

1. IN AN APPARATUS OF THE CLASS DESCRIBED THE COMBINATION OF FRAMEMEANS, A REEL HAVING A COIL OF WIRE OR THE LIKE WOUND THEREON, MEAN FORROTATABLY SUPPORTING SAID REEL ON SAID FRAME MEANS, FESTOON MEANSCOMPRISING A FIRST WIRE GUIDE MOUNTED ON SAID FRAME MEANS, A FESTOON ARMPIVOTALLY MOUNTED AT ONE END THEREOF ON SAID FRAME MEANS, AND A SECONDWIRE GUIDE MOUNTED AT THE OTHER END OF SAID FESTOON ARM AND MOVABLERELATIVE TO SAID FIRST WIRE GUIDE BY PIVOTAL MOVEMENT OF SAID FESTOONARM ABOUT ITS PIVOT FOR STORING WIRE DRAWN FROM SAID REEL BETWEEN SAIDFIRST AND SECOND WIRE GUIDES, MEANS EXTENDING BETWEEN SAID FESTOON ARMAND SAID FRAME MEANS FOR MAINTAINING WIRE DRAWN OFF OF SAID SECOND WIREGUIDE UNDER SUBSTANTIALLY CONSTANT TENSION OVER A PREDETERMINE RANGE OFPIVOTAL MOVEMENT OF SAID FESTOON ARM, A BRAKE DRUM CARRIED BY SAID REEL,BRAKE SHOE MEANS FOR SAID BRAKE DRUM, BRAKE MOUNTING MEANS FOR MOUNTINGSAID BRAKE SHOE MEANS ON SAID FESTOON ARM, BRAKE SPRING MEANS BETWEENSAID BRAKE MOUNTING MEANS FOR MOUNTING SAID BRAKE SHOE FOR YIELDINGLYBIASING SAID BRAKE SHOE MEANS INTO ENGAGEMENT WITH SAID BRAKE DRUM OVERA PREDETERMINED RANGE OF MOVEMENT OF SAID FESTOON ARM, AND SAID BRAKEMOUNTING MEANS AT A PREDETERMINED POSITION OF SAID FESTOON ARMCOLLAPSING SAID BRAKE SPRING MEANS TO DISPOSE SAID BRAKE SHOE MEAN INSELF-ENERGIZING AND SUBSTANTIALLY NON-YIELDING ENGAGEMENT WITH SAIDBRAKE DRUM.